Thermostatic device



*May 5, 1931 G. H. scHwEDLER 1,803,565

THERMOSTATI C DEVI CE Filed Sept. l, 1927 @Ma/. @adm 2? i www.

Patented May 5, 1931 PATENT OFFICE GUSTAVE H. SCHWEDLER, F KANSAS CITY, MISSOURI THERMOSTATIG DEVICE Application led September 1,1927. Serial No.`216,882. i TT".

My invention relates to a thermostatic device which is particularly adapted for use with electrically heated devices, and one object is to provide a thermostat of this character which will automatically open an electric circuit before the heating device connected thereto can become overheated.

A further object is to provide a thermostat which may be adjusted to open the electric circuit at any predetermined time.

Another object is to provide a. thermostat of simple construction and which may be easily attached to electrically heated devices of dierent kinds.

A further object is to so construct the parts of the thermostat that they can be readily assembled and will be so designed as to insure good electrical connections.

In order that the invention may be fully 2o understood, reference will now be had to the accompanying drawing, in which:

Fig. 1 is a vertical section of the thermostatic device on line 1-1 of Fig. 2.

Fig. 2 is a vertical section on line 2 2 of rig. 1.

Fig. 3 is an irregular vertical section on line 3-3 of Fig. 1.

, Fig. 4 is a plan view of the thermostatic device showing the means whereby it may be 3o set to open an electric circuit at any desired time.

Fig. 5 is .a detail perspective view of a plate upon which several parts of the thermostatic device are mounted.

Fig. 6 is a detail perspective of a selfopenmg switch employed in carrying out the invention.

Fig. 7 is a section on line 7 of Fig. 1, showing a circuit closer.

Fig. 8 is a diagram of the thermostatic circuits connected to a pair of heating elements.

Referring in detail to the different parts, 2 designates a case consisting of a removable cover 4 and a back plate 6, which latter consists of suitable insulating material such as vulcanized rubber.

8 designates a switch which is mounted at ,Y 4its upper portion upon a pivot 10 carried by a. pair of arms 12 projecting forwardly from a plate 13 fixed to the back plate 6. The lower portion of the switch 8 is adapted to engage a pair of oppositely-disposed contacts 4 and 14a which are secured to the back --1 plate 6. A spring 16 which is connected at '55 one end to the back plate 6` and at its opi posite end to the upper portion of the switch 8A tends to draw the lower portion of the latter outof engagement with the contacts 14 and 14a. 60

18 designates apushbutton operably mounted in the front portion of the cover 4 and normally held in outward position by a spring 20. W'hen pressed inwardly the push button 18 engages the intermediate U-shaped por- 65 tion 22 of the switch 8 and forces the latter backwardly into engagement with the contacts 14 and 14a where it is held by a latch 24 which is pressed downwardly by a spring 26 into engagement with the upper edge of the lower transverse portion 28 of said switch 8. The latch 24 is mounted at its rear end upon a pivot 25 carried by ears 27 projecting from the lower portion of the plate 13. Said latch 24 also constitutes the armature 75 of an electromagnet 30 depending from a. bracket 32 secured to the plate 13.

34 designates a thermal circuit breaker which consists of a resistance coil 86, and two plates 88 and 40, the former of which is 80 adapted to expand to a greater extent than 1the latter when subjected to heat and cause a contact 42 to engage an adjustable contact 44.

VThe contact 42 is secured to the free ends of contact 44 is threaded in a bracket 45 secured to the back plate 6 of the case 2.

46 designates a shutter mounted upon a pivot 48 and adapted to close an air outlet 50 in the upper portion of the case 2. The shutter 46 is provided with a handle 52which eX- tends outwardly through a slot in the case 2 and over a bracket 54 secured to the front of the case 2 and having a horizontally disposed suitably calibrated portion to indicate minutes or other suitable periods of time.

56 designates a screened inlet in the lower portion or' the case 2 and through which a current of air may pass to the outlet 50 for a purpose which will hereinafter appear.

In order that the circuits through the thermostatic device and the heating elements of an electric device may be traced, reference will now be had to the diagrammatic view disclosed by Fig. 8, in which 58 designates a male connector through which the current enters and passes through a conductor 60, contact 14, switch 8, contact 14a, a conductor 62, female and male connectors 64 and 66, respectively, the heating elements 68'of the electric device, male and female connectors 7 0 .and 72, respectively, a conductor 74, resistance coil 36, conductor 76, and a male connector 7 8'. As the plates 38 and 40 of the circuit closer 34 becomes heated to a predetermined temperature by radiation from the resistance coil 36, said plates 38 and40, by reason of the greater expansion of plate 38, carry the contactf42 against the contact 44 and thereby close a shunt 79 leading from said contact 44 and including the electromagnet 30 and a resistance coil 80, which reduces the current in said shunt and thereby prevents burningrout of the electromagnet 30. Current passing through the shunt energizes the electromagnet 30 and causes it to attract the armatu're'24 out of engagement with the switch 8 which is then instantly opened by the spring 16, thereby opening both the main and shunt circuits. The time in which the circuit closer 34 closes the shunt circuit 79 may be regulated by open ing the shutter 46 to the proper degree, it beingv understood that the' air circulating through the case 2 from the inlet -56 to the outlet 50 will have a cooling effect upon the circuit closer 34 and retard its operation in accordance with the volume and rapidity at which the air is permitted to flow through the caseV 2. The 'connectors 58 and 78 maybe connected to an electric light circuit or other source of current through the usual extension cord and fittings, or in any other suitable manner. y

From the foregoing description it ris apparent that I have provided a thermostatic device which maybe set to open an electric circuit at any predetermined time, and while I have shown one forni of said device I`reserve the right to all such other vforms and modifications thereoflas properly fall within the spirit and scope ofthe inventionV as claimed.

Having thus described' my invention,whatI claim and desire to secure by Letters Patent, Y

shutter pivotally mounted in the case for 

